Update README.md

Update to include license information about data

README.md

@@ -2,7 +2,9 @@
 license: mit
 ---
 
-# Whereabouts
+# Whereabouts: Reference databases
+
+This is a space containing reference databases to be used by [whereabouts](https://github.com/ajl2718/whereabouts).
 
 Whereabouts is a geocoding package in Python that implements some clever record linkage algorithms in SQL using DuckDB. The package itself
 is available at [whereabouts](https://github.com/ajl2718/whereabouts) and can be installed via
@@ -11,6 +13,14 @@ is available at [whereabouts](https://github.com/ajl2718/whereabouts) and can be
 pip install whereabouts
 ```
 
+## Important note about licenses
+Note that while the code from this package is licensed under the MIT license, the pre-built databases use data from data providers 
+that may have restrictions for particular use cases:
+- The Australian databases are built from the [Geocoded National Address File](https://https://data.gov.au/data/dataset/geocoded-national-address-file-g-naf) with conditions of use based on the [End User License Agreemment](https://data.gov.au/dataset/ds-dga-e1a365fc-52f5-4798-8f0c-ed1d33d43b6d/distribution/dist-dga-0102be65-3781-42d9-9458-fdaf7170efed/details?q=previous%20gnaf)
+- The US databases are still work-in-progress but are based on data from [OpenAddresses](https://openaddresses.io/) and so any work with whereabouts based on US address data should adhere to the [OpenAddresses license](https://github.com/openaddresses/openaddresses/blob/master/LICENSE).
+
+Please ensure that you are adhering to these licenses in your applications.
+
 ## Installation of reference databases
 Once the package is installed you will need to install a geocoding database, which has been built from a country's or region's address data. 
 This repo contains a collection of these databases for different countries and regions. Currently it has files for